Conveyor systems comprising conveyors, associated chutes and ore transfer stations are commonly used to convey large tonnages of ore in mining and mineral processing applications in order to transfer ore between mining and rock crushing stages, stockpiles or other unit processes. The open conveyor system geometry provides an opportunity to measure characteristics of the conveyed ore as it is being conveyed prior to downstream processing stages. For example, it may be desirable to measure the grade of specific elements or minerals in the ore with such on-line measurements.
The on-line measurement of ore grade may be used in a number of different ways to benefit mining. In sensor based bulk ore sorting, rapid detection of selected minerals or elements may be used to determine the economic value of consecutive ore parcels as they pass a sensor in a continuous stream. This information can be used to operate diverter or flop gates placed downstream of the sensor to sort the ore parcels into different stockpiles or channels. The resulting low grade ore streams may be diverted away from the relatively expensive comminution process, leading to potentially significant improvements in productivity. Bulk ore sorting can be applied to mining operations to lift productivity. Besides bulk ore sorting applications, sensors on conveyor systems may be used to determine longer term ore grades or rock-type trends.
Typically, benefit from sensing is maximised if the sensors are used in an on-line configuration, such that measurement information can be relayed to downstream processing plant in real-time, or at least in near real-time, such that a plant operator can act on the measurement information, within critical periods defined by either process residence or delay times.
However, there are few sensors suitable for bulk ore sorting as the ore sorting sensor ideally has a large sensing volume, and be able to measure ore on conveyors that contain long metallic cores. The sensor ideally can measure a significant fraction of the mineral stream very rapidly, and also enable quantitative measurements to be made. The sensor should also be able to measure groups of piled rocks in the conveyed ore stream.
It would therefore be of benefit to the mining industry if rapid sensors compatible with on-line measurement of materials on ore conveyor systems were developed.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters: form part of the prior art base; were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application; or could have been understood, regarded as relevant or reasonably expected to have been combined by a person skilled in the art.